SACN + NIH ODS + Vegan Society

Vegan vs Vegetarian Vitamin D: Why D3 Is Usually From Lanolin

The vegan vs vegetarian vitamin D question is partly biology and partly sourcing. The biology is identical across the two diets: at northern latitudes you cannot make enough D in your skin during winter, so you need a supplement. The sourcing question is where the diets diverge, because almost all commercial vitamin D3 starts as sheep wool lanolin.

The short answer. Take 10 mcg (400 IU) of vitamin D daily October to March if you live in the UK or northern US, year-round if you have dark skin or limited sun exposure. Vegans should buy a supplement explicitly labelled lichen-derived D3 (cholecalciferol). Vegetarians can use any standard D3 supplement (lanolin-derived D3 is acceptable to most lacto-ovo vegetarians). D2 (ergocalciferol) works but raises serum 25-OH-D about 1.7x less efficiently per IU.

The lanolin question, settled

Vitamin D3 (cholecalciferol) is manufactured industrially in two main pathways. The dominant pathway uses 7-dehydrocholesterol extracted from sheep wool lanolin, then exposes it to UV light to convert it to cholecalciferol. Lanolin is a wax secreted by the sebaceous glands of sheep and collected from sheared wool. The sheep are not harmed by the extraction. The product is acceptable to most vegetarians under any of the common definitions, including those based on harm avoidance rather than strict animal-product avoidance. It is not acceptable to vegans, because the Vegan Society and analogous certifying bodies define veganism to exclude all animal-derived ingredients regardless of harm.

The second pathway uses lichen, specifically certain species of Cladonia, which naturally synthesise cholecalciferol when exposed to UV. Industrial lichen D3 has been commercially available since the mid-2010s and is now standard in vegan supplement ranges. The biochemistry of the end product is identical to lanolin D3; the molecule is the same. The cost is higher because lichen yields are lower and the extraction process is more involved, so vegan D3 supplements typically cost 1.5 to 3x more than lanolin D3 of the same dose.

The third option is D2 (ergocalciferol), which is produced from ergosterol in yeast or fungi by UV irradiation. D2 has always been vegan-compatible. The drawback is biological efficacy, addressed in the next section.

D2 vs D3 efficacy, with the published numbers

The most cited meta-analysis on this is Tripkovic and colleagues at the University of Surrey, published in the American Journal of Clinical Nutrition in 2012. They pooled trials directly comparing D2 and D3 supplementation and found that D3 was approximately 1.7 times more effective at raising serum 25-hydroxyvitamin D (the standard clinical marker of vitamin D status) than D2. The advantage was most pronounced with bolus dosing and at lower daily doses; at high daily doses sustained over weeks, the gap narrowed to roughly 1.1 to 1.3x.

The mechanistic explanation: D3 binds more tightly to the vitamin D-binding protein in blood, which keeps it in circulation for longer and allows more conversion to the active 25-hydroxyvitamin D form in the liver. D2 dissociates from the binding protein faster and is cleared more quickly. Both forms work; both are recognised by the active receptor. The practical implication for vegans is that if you choose D2 (ergocalciferol from UV-treated mushrooms or yeast) rather than lichen-derived D3, you should dose 1.5 to 2x higher to achieve the same serum 25-OH-D rise.

For most vegans the simpler answer is to spend the extra and buy lichen D3. A typical bottle of 100 lichen D3 tablets at 1,000 IU is around 12 to 18 GBP in the UK and 8 to 15 USD in the US, which works out to under 20 pence (or cents) per day. The cost differential against lanolin D3 is real but small in absolute terms.

How much and when

Population	UK SACN	US IOM	Endocrine Society
Adults to age 70	10 mcg (400 IU) daily Oct to Mar	15 mcg (600 IU) daily year-round	1,500 to 2,000 IU daily for status
Adults over 70	10 mcg daily year-round	20 mcg (800 IU) daily	1,500 to 2,000 IU daily
Pregnancy	10 mcg daily	15 mcg daily	1,500 to 2,000 IU
Breastfeeding	10 mcg daily	15 mcg daily	4,000 to 6,000 IU to enrich milk
Infants 0 to 12 months	8.5 to 10 mcg (340 to 400 IU) daily	10 mcg (400 IU)	400 to 1,000 IU
Children 1 to 18 years	10 mcg daily	15 mcg daily	600 to 1,000 IU

The conservative path: 10 mcg (400 IU) daily October to March if you are in the UK or northern US. Year-round at 10 to 25 mcg if you have darker skin, work nights, cover up outdoors, are pregnant, or are housebound. Targeting serum 25-OH-D in the 50 to 75 nmol/L range is the SACN sufficiency threshold; some endocrinology groups argue for 75 to 125 nmol/L. Above 250 nmol/L is potentially toxic. The tolerable upper intake is 100 mcg (4,000 IU) per day for adults.

Practical buying notes for vegans: look for the Vegan Society trademark, the words lichen-derived, or check the supplement's website for source declarations. Examples of UK-available vegan D3 brands include Nature's Aid, Vega, Together Health, and Vegan Society's own range. In the US, NOW Foods, Nordic Naturals, and Garden of Life sell vegan D3 lines. Read the label, not just the front of pack.

UV-treated mushrooms, briefly

Mushrooms contain ergosterol that converts to ergocalciferol (D2) when exposed to UV light. Some commercial mushroom growers expose their mushrooms to UV during or after cultivation and label the resulting product as a vitamin D source. A 100 g serving of UV-treated white button or maitake mushrooms can supply 5 to 10 mcg of D2. Untreated mushrooms supply essentially none.

Treatment is not the default; you have to look for it on the pack. UK supermarkets carry occasional UV-mushroom lines (Sainsbury's and Tesco both stock them intermittently). US supermarkets carry them more consistently in the natural foods section, often labelled "vitamin D mushrooms."

The practical take: UV mushrooms are a useful seasonal addition to a vegan diet but they are not a substitute for a supplement, partly because of inconsistent availability and partly because D2 efficacy is lower per IU than D3. Treat them as a bonus when you can find them, not a strategy.

Testing and what to do with the result

The standard test is serum 25-hydroxyvitamin D, often abbreviated as 25-OH-D. The UK NHS reference ranges (from SACN) are below 25 nmol/L deficient, 25 to 50 nmol/L insufficient, 50 nmol/L and above sufficient. US Endocrine Society ranges are below 50 nmol/L deficient, 50 to 75 nmol/L insufficient, 75 to 250 nmol/L sufficient. There is a real if narrow disagreement between the two bodies on what "sufficient" means.

If you are vegan, in your first winter after transitioning, and have not been supplementing, test in February or March; that is when stores will be lowest. If your result is below 50 nmol/L, the published clinical algorithms are to take 25 to 50 mcg (1,000 to 2,000 IU) daily for 8 to 12 weeks to repair, then drop back to 10 to 25 mcg maintenance. Retest at the end of the repair window. If you have malabsorption (coeliac disease, inflammatory bowel disease, gastric bypass), discuss high-dose protocols with a clinician.

Avoid taking a megadose vitamin D supplement (50,000 IU weekly is a common UK private prescription) without medical supervision. Toxicity (hypercalcaemia, kidney damage) is rare but real at sustained intakes above 10,000 IU daily over months.

Pregnancy note. Vitamin D status during pregnancy affects infant bone development and may affect maternal pre-eclampsia risk. The UK national guidance recommends 10 mcg daily during pregnancy and breastfeeding for all women regardless of diet. Vegan and vegetarian pregnant women should ensure their prenatal vitamin contains D3 (lichen-derived for vegans). See vegan vs vegetarian pregnancy for the detailed nutrient walk-through.

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Frequently asked questions about vitamin D

Is vitamin D3 vegan?

Most vitamin D3 (cholecalciferol) on the market is extracted from sheep wool lanolin and is therefore not vegan, though it is acceptable to most lacto-ovo vegetarians and to those following a Jain or Hindu lacto-vegetarian tradition that allows wool-derived products. A small but growing share of vitamin D3 is produced from lichen, and lichen-derived D3 is labelled as suitable for vegans. Brands using lichen D3 typically carry a Vegan Society trademark or explicit vegan certification on pack. Look for the words lichen-derived or check the brand's website if it is not on pack.

Is D2 (ergocalciferol) as effective as D3?

Per IU dosed, D3 raises and maintains serum 25-hydroxyvitamin D more efficiently than D2, particularly at lower doses and over longer durations. The Tripkovic meta-analysis published in the American Journal of Clinical Nutrition in 2012 found D3 was approximately 1.7x more effective at raising serum 25-OH-D than D2 across mixed trials. The gap narrows at higher doses and shorter durations. For vegans choosing between lichen D3 and UV-mushroom D2, lichen D3 is the better-evidenced option. If only D2 is available or affordable, dose a little higher to compensate.

How much vitamin D should I take in winter?

Public Health England (now UK Health Security Agency) and the Scientific Advisory Committee on Nutrition recommend that everyone in the UK should take 10 mcg (400 IU) of vitamin D per day during October to March, regardless of diet. The Endocrine Society in the US suggests 600 to 800 IU daily for adults under 70 and 800 to 1,000 IU for adults over 70. People with dark skin, those who cover up outdoors, and shift workers may need higher doses year-round. Vegans should confirm the supplement is lichen-derived D3 or, less ideally, ergocalciferol D2.

Can I get enough vitamin D from food alone?

Almost no one does, on any diet. The natural food sources of vitamin D are oily fish (salmon, mackerel, sardines), egg yolks, and some types of mushroom. A 100 g portion of salmon supplies about 13 mcg. An egg yolk supplies about 1 mcg. UV-treated mushrooms can supply 5 to 10 mcg per serving but most retail mushrooms are not UV-treated. Fortified foods (some plant milks, some breakfast cereals, fortified margarines) add a few micrograms per serving. The reason almost everyone needs a supplement in winter is that food cannot easily reach the 10 mcg per day target, particularly for vegans whose options narrow to fortified plant milks and UV mushrooms.

Is the sun enough in summer?

Above about 50 degrees latitude (which covers most of the UK, northern Europe, and Canada), the sun is too low in the sky to make vitamin D in skin from October to March. From April to September, exposing forearms and lower legs to direct sun for 10 to 15 minutes around midday a few times a week is enough for most fair-skinned adults. People with darker skin need substantially longer exposure to make the same amount; those with very dark skin may need supplementation year-round. SPF 30 sunscreen reduces vitamin D synthesis by around 95 to 99% when properly applied. The published SACN guidance assumes summer sun handles your needs and winter supplementation fills the gap, which is a reasonable working model for most people.

Do vegetarians who eat dairy and eggs get enough vitamin D?

Better than vegans on food alone, but still rarely enough. UK dairy is not routinely fortified with vitamin D (unlike US dairy, where 100 IU per cup fortification is standard). UK eggs contribute about 1 to 2 mcg per egg. A US lacto-ovo vegetarian eating one egg and 500 ml of fortified milk daily could pick up around 7 mcg from food, close to the SACN 10 mcg target. A UK lacto-ovo vegetarian on the same pattern would pick up around 3 mcg. The bottom line: vegetarians and vegans alike should follow the SACN winter supplementation guidance, and the choice of D2 vs D3 vs lichen-D3 is the variable that depends on diet ethics.

Sources cited. NIH ODS Vitamin D fact sheet for health professionals; SACN Vitamin D and Health report 2016; Tripkovic L et al. Comparison of vitamin D2 and vitamin D3 supplementation in raising serum 25-hydroxyvitamin D status, Am J Clin Nutr 2012; 95: 1357-1364; The Vegan Society Vitamin D guidance; BDA Vitamin D food fact sheet; Holick MF et al. Evaluation, treatment, and prevention of vitamin D deficiency: an Endocrine Society clinical practice guideline, J Clin Endocrinol Metab 2011; 96: 1911-1930. All values as of May 2026.